What is the primary purpose of secondary flight controls in aviation?

The primary purpose of secondary flight controls is to improve aircraft performance and aid the pilot. Secondary flight controls include devices such as flaps, slats, ailerons, and trim systems that supplement the primary controls and enhance the aircraft's operational capabilities. For example, flaps increase lift during takeoff and landing, allowing for shorter runway requirements and improved safety margins. Trim systems help to relieve pilot workload by maintaining the aircraft in a desired flight attitude without the need for constant pressure on the control yoke or stick.

While secondary flight controls may indirectly influence passenger comfort, utility, weight reduction, or fuel efficiency, their main function is directly tied to enhancing the handling characteristics of the aircraft and aiding the pilot in achieving better performance during different phases of flight, such as takeoff, landing, and maneuvering.